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Cornwall to Montréal

Warnings

Forecast

Marine Forecast

Issued 03:00 PM EDT 21 July 2026

Tonight and Wednesday.

Strong wind warning in effect.

Wind south 15 to 25 knots becoming southwest 15 late this evening then increasing to southwest 15 to 25 early Wednesday morning. Wind becoming west 15 Wednesday evening.

Showers ending Wednesday morning. Risk of thunderstorms late this afternoon and this evening.

Extended Forecast

Issued 06:00 AM EDT 21 July 2026
Thursday Wind southwest 15 to 20 knots diminishing to southwest 10 to 15 late in the day.
Friday Wind southwest 10 to 15 knots.
Saturday Wind light.

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Map of St. Lawrence - St. Lawrence River marine weather areas Miramichi North Cape Port Menier Roberval Airport Normandin Mistook Jonquière CFB Bagotville Cap-Chat Île Bicquette Charlo North Bay Airport Yarmouth Airport Brier Island St. Stephen Saint John Airport Point Lepreau Greater Moncton Roméo LeBlanc Int'l Airport Miscou Island Kouchibouguac Kouchibouguac Grand Manan Fundy Park (Alma) Bas Caraquet Bathurst Airport Lac Saint-Pierre Pointe-Noire Île-d'Orléans - Quai de St-Jean Pointe-des-Monts L'Assomption Sept-Îles Airport Pointe Claveau Pointe de l'Islet Trois-Rivières Airport L'Isle-aux-Grues Deschambault Île Rouge Montréal-Trudeau Int'l Airport Montréal Metropolitain Airport Lac Memphrémagog Sainte-Anne-de-Bellevue Cap-Rouge Saint-Anicet Baie-Comeau Airport La Pocatière Pointe-au-Père New Carlisle Mont-Joli Airport Gaspé Airport Lake Nipissing - 45152 Rivière-la-Madeleine Beauport Cap-d'Espoir
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land station Land Station
Ice Conditions

There is no ice forecast issued for this area.

Warnings

Warnings (In effect)

Strong wind warning in effect

Cornwall to Montréal

Issued 3:00 PM EDT 21 July 2026

'Strong' winds of 20 to 33 knots are occurring or expected to occur in this marine area. Please refer to the latest marine forecasts for further details and continue to monitor the situation through Canadian Coast Guard radio.

Watches (In effect)

Squall watch in effect

Cornwall to Montréal

Issued 10:03 AM EDT 21 July 2026 Today, between 3 pm and 8 pm, conditions will be favourable for the development of squalls accompanied by gusts of up to 45 knots and frequent lightning.

Vessels without lightning protection should make their way to shore immediately. Mariners are advised to prepare for potential squalls. Vulnerable vessels are most at risk and should seek safe harbour if underway. Consider delaying or postponing travel in areas under the Squall Watch.

Please continue to monitor alerts and forecasts issued by Environment Canada. For more information monitor Canadian Coast Guard radio or Weatheradio stations.

Synopsis

Technical Marine Synopsis

Issued 3:00 PM EDT 21 July 2026 Tonight and Wednesday At 3:00 p.m. EDT today low 990 mb located over James Bay.
By 8:00 p.m. EDT Wednesday low 994 mb located over northern Quebec.

At 7:00 a.m. EDT Wednesday cold front from low located over
Montréal.
By 8:00 p.m. EDT Wednesday cold front from low located over
Pointe-des-Monts.

St. Lawrence - St. Lawrence River Area

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Marine Weather for Canada

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